1. Field of the Invention
The present invention relates to a substrate with a crystallized silicon film and a manufacturing method thereof. Specifically, the present invention relates to a substrate a with crystallized silicon film with high crystallinity, high adhesiveness, and excellent optoelectronic properties, which is formed by depositing silicon chloride as a precursor on a flexible substrate through microwave plasma enhanced chemical vapor deposition.
2. Description of Related Art
Recently, industries are desirable to develop thinner and lighter electronic devices with multiple functions and low manufacturing cost to meet customers' needs. In order to satisfy the needs described above, the industries focus on using flexible polymer substrates for lightening the electronic devices. The use of the flexible polymer substrates in the electronic devices not only can expand the application ranges and market values of the electronic devices, but also can reduce the manufacturing cost thereof due to the applications of a roll-to-roll process. However, the polymer substrate generally has a lower melting point, such that the applications of the polymer substrate are limited, and the manufacturing processes for the electronic devices are also limited.
The manufacturing process of flexible optoelectronic devices with the amorphous silicon film has been fully developed. However, the said development of flexible optoelectronic devices is still restricted due to the unstable optoelectronic properties of the amorphous silicon film. Nowadays, it is known that the crystallized silicon film has better optoelectronic properties and carrier mobility than the amorphous silicon film, which improves many disadvantages of the amorphous silicon film.
The recent methods for manufacturing crystallized silicon film mainly comprise: solid phase crystallization, excimer laser annealing, metal-induced crystallization, and direct deposition. The process of solid phase crystallization includes the step of heating the silicon material in a prolonged duration time to re-nucleate silicon atoms. However, the process temperature thereof have to be 600° C. or higher. The process of excimer laser annealing includes the step of irradiating the amorphous silicon film with high energy laser to instantaneously melt the amorphous silicon film and then recrystallize to form the crystallized silicon film. However, the process temperature thereof have to be 400˜600° C. The process of metal-induced crystallization includes the step of adding a specific metal into the amorphous silicon film to induce the eutectic reaction between the metal and the amorphous silicon, or to form the metal silicide thereof, to lower the temperature required for solid phase crystallization to about 250˜50020  C. In addition, the process of direct deposition is performed by physical vapor deposition, thermal chemical vapor deposition, plasma enhanced chemical vapor deposition, or hot filament chemical vapor deposition in combination with a process of heating the base, high density plasma assisting apparatus or laser treatment to sufficiently grow the crystallized silicon film. However, the process temperature thereof might still be 250˜350° C.
According to the above mentioned techniques for manufacturing the crystallized silicon film, the former three methods require high temperature for recrystallization of the amorphous silicon. Even the process temperature for direct deposition method is relatively lower, it still has to be 250˜500° C. In addition, the crystallinity of the crystallized silicon films prepared by the above mentioned methods are rather low. Due to the low melting temperature of the flexible polymer substrate, it is difficult to directly form a crystallized silicon film with high crystallinity and excellent optoelectronic properties on a flexible polymer substrate.
Accordingly, it is desirable to provide a method of directly forming a crystallized silicon film with high crystallinity on a flexible polymer substrate, which is beneficial to the development of slimmer and lighter electronic devices.